Barrel of firearms



Dec. 9, 1930. K, wlTZELL 1,784,325

BARREL OF FIREARMS Filed Nov. 18. 1929 lm/erJ-rnw A Mz ma (/1 ?atentedDec. 9, 1930 UNITED STATES KARL WITZE-LL, OFBERLIN-LICHTERFELDE,"GERMANY, ASSIGNOR TO RHEINISCHE METALLWAAREN- UNDMASCHINENFABRIK, OF DUSSELDORF-DERENDORF, GER- MANY, A CORPORATION OFGERMANY BARREL FIREARMS Application filed November 1 8, 1929, Serial No.408,059, and in Germany June 1, 1928.

The life of the barrels of fire arms is only limited as, during firing,burning out particularly of the loading compartment and the adjoiningportions of the barrel grooves 5 or furrows occurs. To make use of theportion of the barrel still fit for service, it is customary to replacethe burnt out part of the barrel only by an insertion piece. When usingthis method it is, however, absolutely necessary that the insertionpiece jointless connects to the barrel and it is particularly requiredthat all grooves or furrows of the inserted new piece stepless mergeinto the inside of the barrel. To obtain this, means must be provided bywhich the new piece inserted into the barrel can easily be brought inthe proper angular position and may then be fixed in this position, sothat it is abs-olutely prevented from moving during firing and turningunder the influence of the grooves or furrows. The insertion piece mustalso be easily replaceable or exchangeable.

According to the present invention these objects are obtained by thefact that the insertion piece, snugly fitting the correspondingly boredbarrel, carries at its front face one or more projections which engagecorrespondingly shaped openings provided in the adjoining front face ofthe barrel. Preferably the adjoining faces of the insertion piece and ofthe barrel are formed as helicoidal surfaces of equal pitch thedirection of which is opposite to that of the grooves or furrows of thebarrel. Each of the helicoidal surfaces is provided with a stepped faceor shoulder extending in the direction of the axis of the bore. Thehelicoidal sur- 40 faces are easy to make and the stepped face orshoulder of the insertion piece may, without any difliculty, be arrangedin such a position that, when it is brought into contact with thecounter-face of the barrel, the

grooves or furrows of the insertion piece PATENT caries smoothly andstepless merge into the grooves or furrows of the barrel.

In the accompanying drawing a longitudinal section of one constructionaccording to the invention is shown by way of example in connection witha barrel having an inserted bored piece and an insertion cartridgemagazine.

In the bored out hind portion of the barrel b a spare tube'or insertionpiece a is fitted which contains the loading chamber and a portion ofthe grooves or furrows. The adjoining faces of the barrel 6 and of theinsertion piece a are formed as single helicoidal surfaces 03 of equalflat pitch the direction of which is opposite to that of the grooves orfurrows. The shoulders or stepped faces 0 of the helicoidal surfaces areof the same direction as the axis of the bore and occupy such a positionat both parts that, when the shoulders engage each other, the grooves orfurrows of both parts exactly fit or merge into each other. Duringfiring, the forward movement of the projectile causes the helicoidalsurface d of the insertion piece a to be firmly pressed against thehelicoidal surface of the barrel. Moreover the torque caused by thegrooves or furrows and acting upon the insertion piece a is transferredto the barrel 2) by means of the stepped faces or shoulders 0 withoutany possibility of relative rotation or displacement of the twotube-like parts a and b. If it is desired to remove the insertion piecea, it is, for the purpose of loosening, first turned with regard to thebarrel .7) in the direction of the grooves or furrows, whereupon thehelicoidal surfaces 01 disengage the two parts, so that the insertionpiece a may easily be pulled out to the rear of the barrel.

What I claim is:

In a barrel of fire arms provided with grooves or furrows and anexchangeable i11- sertion piece, in combination a projection at thefront face of said insertion piece and a corresponding opening in therear face of said barrel adjoining the front face of said insertionpiece, said adjoining front faces of said insertion piece and saidbarrel being formed as helicoidal surfaces of equal pitch the directionof which is opposite to that of said grooves or furrows and being eachprovided with avstepped face or shoulder extending in the direction ofthe axis of said barrel. v

In testimony whereof I have aflixed my signature.

KARL WITZELL.

